When rendering, Cycles and Eevee only renders some materials
I’m not sure the materials go missing. Are you talking about what look like reflections of the surroundings on the sword? I have repeatedly thought something was wrong with my metallic materials when that happened in material preview but disappeared in render, but it turns out that’s just because the world background in the material preview is automatically an HDR texture, and in cycles or EEVEE render it defaults to flat gray which makes no reflections.
Just change the World background to something interesting (an environment texture from blender’s own data files works great) and metallic materials should look much better .
As for the glow effect, this is likely because you enabled bloom while using EEVEE, but then switched to cycles render. The bloom will still appear in material preview. You can create a bloom like effect for cycles using the glare node in the compositor .